


Amalgaster

by reivuu



Category: Undertale (Video Game)
Genre: Body Horror, Gen, and no one technically dies but they're functionally gone, based on Bromalgamate AU, the body horror is mostly limited to the first chapter
Language: English
Status: In-Progress
Published: 2015-11-22
Updated: 2017-01-15
Packaged: 2018-05-02 18:53:25
Rating: Teen And Up Audiences
Warnings: Major Character Death
Chapters: 9
Words: 9,164
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5259872
Author URL: https://archiveofourown.org/users/reivuu/pseuds/reivuu
Summary: <blockquote class="userstuff">
              <p>If Sans and Papyrus were two halves of Gaster, then if they were fused together...</p>
            </blockquote>





	1. Amalgamation

**Author's Note:**

> This started as my attempt at making the idea of Zarla's Sixbones AU remotely okay after stumbling across it late at night. I may or may not have succeeded.

> ENTRY NUMBER 22

Sans showed up on my doorstep today. Papyrus fell down, and Sans thinks I can fix him somehow. I… I don’t know how he heard about my Determination experiments, or how much he knows, but he’s so desperate… He doesn’t think Papyrus can get any worse. I can’t tell him how much worse it could get.

> ENTRY NUMBER 23

I couldn’t refuse after all. I’ve started Papyrus on the Determination injections. Maybe… Maybe if I can isolate him, he won’t degenerate into… into another… no. No no no, I can’t think about that. I just have to keep working. Sans is still here. I’m the only chance he has. I can’t screw this up, not this time.

> ENTRY NUMBER 24

I never actually see Sans come or go, but I keep finding him down here, visiting Papyrus. He hasn’t gone any deeper into the labs, as far as I know. He hasn’t found _them_. The DT treatment hasn’t done anything yet, but Papyrus hasn’t turned to dust yet, so I guess that’s a good sign?

>  ENTRY NUMBER 25

Papyrus opened his eyes. Sans is thrilled. Please please please let him be okay. He has to be okay.

> ENTRY NUMBER 26

No. No no no no nO NO NO NOT AGAIN–

 

Alphys’ claws shook almost as much as her voice as she fumbled with the voice recorder. _It_ was in another room, a single door separating her from her latest failure. “M-My hyp-pothesis was d-disproven. I-It didn’t… They s-still… I couldn’t… Couldn’t stop it. I n-never should have…”

Papyrus and Sans always were nigh-inseparable. And now… Now they really were inseparable. Melted together. _Amalgamated._

She cut off her recording there, stopping to listen to what was going on in the other room. She couldn’t run away from her mistakes this time… not when they were between her and the lab exit. At least the screaming had died down sooner than expected. They’d gone from screaming each other’s names, to murmuring something she couldn’t make out, and now she swore she could hear something like… contented burbling? Well, if they… if _it_ was docile, now was her chance to escape the corner she’d backed herself into. She took a deep breath and peeked through the doorway.

“G-Guys…?” Oh dear. They were losing their individual forms faster than expected, too… They had already degenerated into a vaguely two-headed blob that was… blackening around the edges? And their faces looked like they were splitting apart, with matching fractures above the right eyes and below the left… The muted burbling stopped sounding like either of the skeleton’s voices as malformed hands rose up from their goopy semblance of a body and _smooshed_ the heads together. 

“AH, MUCH BETTER.”

Alphys stifled a scream, feet frozen to the floor in fear. _It_ was almost entirely black now, save its still bone-white head and hands and a bit below the ‘neck’. Beyond a few skeletal traits, it no longer resembled Sans or Papyrus. It was shaping itself into something else entirely.

“DON'T BE AFRAID, ALPHYS. DO YOU REMEMBER ME?”

She couldn't make out what it was saying—it almost hurt her head just trying to parse it—but it didn’t sound threatening? Maybe it was really just trying to communicate, and if she could just say hi and chat for a minute it would be placated and she could get out of there…

“…” She couldn’t think of any conversation topics. She could barely open her mouth. She could only stare as it ‘stood up’, pulling itself up into a form that towered over her.

“YOU DON'T REMEMBER AT ALL... CAN YOU EVEN UNDERSTAND ME?”

Nothing it said was making any sense, nor was it doing anything to calm Alphys down. It inched back a bit, lowering its head and raising its hands in what looked like an attempt at a calming gesture. Wait, no, the way it waved its hands… Was that sign language?

“GASTER”

G A S T E R

**Notes for the Chapter:**

> This was supposed to take place long after the first set of amalgamates were created (which is why the logs start where the game ones left off). Sans remembered what was public knowledge about her first experiments involving fallen monsters, and he was desperate enough to try anything to save his brother.
> 
> Also I used a work skin to turn Gaster's speech into Wingdings so you can translate it by turning off the skin!


	2. Adaptation

**Summary for the Chapter:**

> Alphys and Gaster begin an uneasy companionship. But it seems Papyrus and Sans are still in there somewhere...

**Notes for the Chapter:**

> Hold off on translating the wingding text until after reading the legible part of the chapter for best results! (Unless the work skin weird out and renders Gaster's text as a monospace font. Then just kinda... skim over it at first?)

> ENTRY NUMBER 27

I forget where I learned sign language, but it sure came in handy! This is still freaky, though. Apparently Sans and Papyrus were once a single being, and their original consciousness took over after they were recombined. He says his name is Gaster. Well, that could have gone worse. I’m not sure if I want to ask for details...

> ENTRY NUMBER 28

Gaster sure seems to know his way around the lab, which is weird, because I know neither Sans nor Papyrus have spent any time down here. And the lab coat he found really suits him, in a weird way. Like he's in his element. There's something really familiar about him, but I can't quite put my finger on it...

> ENTRY NUMBER 29

Undyne called today. She's worried about Papyrus missing his training. How am I supposed to tell her what happened? Gaster overheard the call, and it looks like he's upset. Just how much of Papyrus is left in there...?

> ENTRY NUMBER 30

Gaster made spaghetti for dinner tonight. For some reason. It’s better than the same old ramen, I guess. (But not by much.) He keeps giving me weird looks. He seems almost... apologetic?

> ENTRY NUMBER 31

It has taken some time to adjust to my current situation. Experiencing time in a linear manner feels strange to me now. And Sans and Papyrus, having developed into independent monsters, still influence me. Papyrus particularly regrets being forced to miss his regularly scheduled cooking lesson. Perhaps one day I can meet Undyne in person and resume the lessons. But first, I want to reconnect with my former lab assistant. 

I don't regretti making the spaghetti

 

"It, uh, sure is nice out today, huh?" Alphys never was the best at attempting small talk, but the least she could do was try. After last night's impromptu pasta dinner, it was obvious there was something on his mind. He looked up at her, distracted from the blueprints he had been poring over.

**There's no weather down here,** he signed at her. Oh yeah, they were in a cave...  ~~But then why did Undyne call her that one time~~

"R-Right, yeah... But it's a nice warm cave!"

**Too warm, really. It made it difficult to implement effective cooling systems in the CORE.**

"Yeah, we have to bring in ice from Snowdin just to keep the heat at a manageable level..." At least Ice Wolf was always able to help out, and the river made for easy transport. It wouldn't do for the CORE to overheat, not when it powered so many vital processes in the Underground. "Wait, why do you know so much about the CORE?" Gaster looked away, his expression unreadable.

**I designed it.**  

Wait, what? "You... designed it? But..." Wouldn't she remember the guy who MADE the CORE? Though come to think of it, she couldn't remember exactly who was involved with that project, or even when it was completed... Okay, this was getting freaky.

**Do you remember how I told you I was shattered in an accident? Well, it was related to my temporal studies... According to my observations, I was retroactively erased from existence. But my work remained. Even these blueprints still have my handwriting all over them.**  He held up the blueprints, showing off the strange symbols they were written in.

"You... wrote those?" Suddenly everything started to make sense. Why he fit so well in the lab, why he seemed so familiar, even where those strange blueprints had come from. No one really knew what happened to the last Royal Scientist, other than that they must have made the CORE, and they mysteriously vanished one day. _Retroactively erased_... So then...

"You were the Royal Scientist before me, weren't you?" Gaster nodded. "You made the CORE, designed the DT Extractor, and even did... whatever those temporal studies were... I must look pretty lame in comparison, huh? I've barely done anything right since I got this job..." She couldn't help but feel inferior compared to someone with such important projects under his belt.

Gaster approached her with a smile and put a hand on her shoulder in an attempt at a comforting gesture. (It didn't really work, but the inscrutable texture of his hand was certainly distracting.) "Don't sell yourself short... wait..." He closed his eyes and cleared his throat. "don't sell yourself short. you're doing fine."

That voice... "S-Sans?!" Gaster grinned, taking his hand off of her so he could sign again. 

**He's still in here. Both of them are. Don't worry about them, they're alright.**  Alphys couldn't bring herself to meet his eyes.

"Y-You say that, but... It's my fault you're stuck like that! How can I not worry?!"

**No, it's thanks to you we're not dead!**  

Before either of them could say anything more, a certain robot burst through the main doors. "Alphys~ I'm ready for my maintenance!"

"O-Oh, right! Maintenance! Of course! I'll be right there, Mettaton!" Right, she had to keep Mettaton in good condition, he  _was_ the only thing she'd ever done remotely right, she couldn't mess that up by neglecting his routine maintenance...

Gaster watched as Alphys scurried off to her work area, picking up scattered tools as she ran. "I'll leave you to your work, then," he called as he wandered over to the doors. That discussion certainly could have gone better, but at least he'd said all he wanted to say. Robotics wasn't exactly his area of expertise, so he had some free time while Alphys was occupied. But what to do with this break...? Part of him was eager to not do anything at all, but he knew there was one thing he really couldn't keep putting off.

He couldn't just hide out in the lab forever (well, he COULD, but he knew he SHOULDN'T). Papyrus and Sans were more than just his component parts; they each had friends out there, friends who were probably worried sick about them. Friends who deserved to know where the brothers had gone. It wouldn't be easy, but... He could at least start by meeting Undyne.

He left a note for Alphys by the door in the most legible handwriting he could muster:

> Went to visit Undyne. I'll be back shortly.
> 
> -Gaster

**Notes for the Chapter:**

> Thanks so much for all the positive feedback! I'm about to have a lot less time to write, but I _may_ continue this far enough to get Frisk involved...


	3. Altercation

**Summary for the Chapter:**

> Undyne had to find out what happened to her skeletal apprentice one way or another.

**Notes for the Chapter:**

> So I know I said I had other work to do but I... couldn't stop writing? and I'm too excited about this to save it so have more

 

> ENTRY NUMBER 32

Mettaton's maintenance went well. No major problems. There were some streamers caught in his wheel after the last performance, so I cleaned those out. Progress on his EX body is also going... slowly. But smoothly.

Gaster left while I was busy. Apparently he's gone to see Undyne... Welp, nothing I can do to stop that trainwreck now.

 

Gaster knew he needed to do this. He needed to talk to Undyne, to explain what had happened to Papyrus, even to give his condolences (Papyrus wasn't technically _dead_ , but that was difficult to articulate without a mess of unnecessary details Undyne would never sit through). But in the end... He couldn't face her.

He'd taken a shortcut to Undyne's house (a useful ability he'd picked up from Sans), and lurked in the shadows near her door. She was at home this time of day, practicing piano as usual. The familiar melody filling the cave did nothing to calm his nerves. It was a pity he couldn't see the future of this timeline any more. It would have been comforting to know how this would play out in advance.

Maybe there was one way he could talk to her. He'd already demonstrated the ability to use Sans' and Papyrus' voices. He could just call her with Papyrus' old cell phone, and let Papyrus speak through him... It made travelling all the way to Waterfall a tad redundant, but it was something.

Ring, ring... The piano music abruptly cut off as Undyne rushed for her phone. Gaster almost smiled at the sound of the commotion.

"Papyrus! Where the hell have you been?!" She sounded furious, but he was reasonably certain that was just her way of expressing concern. Now, to figure out how to word this without causing unnecessary panic...

"I-I'm sorry I couldn't come to train with you yesterday, Undyne! I... got sick! But I'm feeling much better now. B-But I still can't come back." There was no getting around it: Papyrus' voice was not the voice of a liar. Even if his story was technically true, none of them really believed it.

"What do you mean, SICK? You don't GET sick, Papyrus! Tell me what's REALLY going on!!"

"I, UM... fell down..." None of him really wanted to do this. It made it hard to focus on using the right voice.

"What? Wait... Why are you calling me..." Undyne kicking the door down was unexpected. "When you're RIGHT OUTSIDE MY HOUSE?!" Eep. Her usual reckless smile fell right off her face as she looked around and found only Gaster leaning against the wall.

"You're not... Papyrus?" Gaster trembled, his form wavering under Undyne's intense scrutiny. The phone he was holding fell through the hole in his palm. Gaster flinched as the sound of his phone hitting the ground came through the one Undyne was holding.

"Who are you, and what have you done to Papyrus?" Her usual boisterous demeanour was replaced with tranquil fury. Quiet Undyne was never pleasant Undyne.

"I ca– I can– I can explain!" Well, at least his momentary loss of coherency distracted Undyne enough to keep her from running him through with the magical spear she'd summoned. "L-Long story! But I'm... Papyrus! Partially. and sans, sort of. And...something else, too?" His body shifted involuntarily, the white band around his neck giving way to a familiar red scarf.

Fury slowly gave way to confusion as Undyne cautiously lowered her spear. "What. Happened. Start talking."

"LAB ACCIDENT! He fell down, IT WAS ALL WE COULD DO TO Recombine" Gaster was usually taller than Undyne, but he was half quivering puddle by then, so she towered over him.

"Lab accident? Does Alphys have something to do with this?" He nodded.

"NOT HER FAULT THOUGH! my fault, SHE FEELS bad enough"

"Okay, so let me get this straight. You're some kind of... fusion? Of Papyrus and Sans?" Another nod. "And you had to miss practice because you can't un-fuse?" More nodding. She dismissed her spear and forced a smile, prompting a relieved sigh from the shuddering amalgamate.

"Well, why didn't you say so in the first place? Hey, if you're free, come inside and we can catch up on that lesson!" She held out a hand to help him up. He latched onto it more out of courtesy than anything as he straightened himself up.

"Yes, I'd... I'D LIKE THAT. SORRY, WE'RE STILL GETTING USED TO THIS."

“Right…” Gaster’s default voice was nigh-unintelligible, but it felt weird for everyone involved to hear Papyrus’ voice coming from his mouth. Still, crisis averted! Probably. For now. There was still a cooking lesson to deal with.

* * *

Bonus art:


	4. Conflagration

**Summary for the Chapter:**

> In catching up on Papyrus' cooking lessons, Gaster tries desperately not to set Undyne's house on fire. But Papyrus' enthusiasm is undying.

**Notes for the Chapter:**

> Thanks so much for all the positive feedback! Over 150 kudos after just a few days! I wasn't expecting this idea to get so popular!

 

> ENTRY NUMBER 33

Gaster hasn't come back from Undyne's yet. I don't know how long he'll be gone, or how well Undyne will take what happened to Papyrus, but... The least I can do is try to be a little productive while he's gone! I'm gathering up all the blueprints I can find with Gaster's weird handwriting on them, so he can look through them when he gets back. Maybe I'll find a project he'll want to continue, so I can help him! I think I'm better suited to be an assistant, anyway. Less chance of me ruining everything.

 

"Yeah, that's it! Stir faster! Harder!"

Gaster was quite sure that the sauce didn't need to be stirred quite so aggressively, but he stirred as fast as he could to appease Undyne. Was it really right to be leading her on like this? Among every timeline he'd seen, through every ending, he'd never found a way to unmake an amalgamation. And he wasn't particularly keen on suffering through a third tragic lab accident to find one.

"Alright, now we turn up the heat!"

"Have mercy on this poor house," he muttered as he turned up the heat to a reasonable cooking temperature. He was not in the mood for dealing with fire-related property damage today, if he could avoid it.

"C'mon, Papyrus, you can do better than that! Here, let me do it!" She shoved him aside, barely acknowledging how deep she drove her elbow into his sludgy body, and cracked up the heat to her typical absurd levels. Much as he wanted to stop her, or at least correct her on his name (though they still hadn't been formally introduced), he was even  _less_  in the mood for upsetting Undyne. So he played the part of Papyrus as best he could for now. He'd have to figure out a way to explain things later...

 ---

Of course, the poor house wasn't really meant to handle that much heat. "Eh, we can go back in and try the spaghetti once the flames die down. I bet it'll taste even better than usual!" There was something fishy about Undyne's sense of taste...  ~~He'd have to save that pun for later.~~

"SO... WHAT DO WE DO NOW?"

"Spar, obviously! You missed your combat training last time, too!" She was certainly eager to fight, considering how quickly she drew her spear.

"uhh... you know i'm still getting used to this body, right?" It hadn't even been 72 hours since he had... amalgamated. (He knew, because he had been keeping track to help him readjust to time moving at a constant pace.) Hardly enough time to relearn how to fight properly. 

"All the more reason not to slack off! C'mon, I'll even go easy on you while you warm up! Show me your combined power!!" She may have had a good point about that, but fighting with Undyne directly was still not something he particularly wanted to be doing. Rather than attack Undyne directly, Gaster sent a volley of bones towards the nearby training dummy. He had always had exceptional control of his magic (something Papyrus inherited, thus Undyne should be aware of), and he wouldn't attack another monster until he knew exactly how much damage he could do.

...He did a fair bit more damage to the dummy than he'd intended to, but Undyne still wasn't satisfied. "Is that all you got? You can do better than that, Papyrus!"

"I'm not..." He really needed to clear this up, but he didn't want to hurt his friend---his friend? Papyrus' friend? He wasn't quite sure where to draw the line. "UNDYNE, I..."

"Hey, I know you've got a lot on your mind, pal. Or minds, however this fusion thing works. That's why I wanted to spar with you so badly! If you can't say it with your mouth, say it with your magic!" With a wave of her summoned spear, she turned his SOUL green, then adopted a battle stance as she awaited his first move. "Now stop running from your problems and face me!"

With no other options left, Gaster pulled together his magic and sent out a weak, but intricate volley of bones. Spelling out words with his attacks probably wasn't what she meant by 'saying it with his magic', but it was something. This way he could spell out what was on his mind. In the attack, he wrote:

**I AM W. D. GASTER        AND I**

 

 

\---

 

> FILE 1 LOADED

 "Yeah, that's it! Stir faster! Harder!"

Gaster was quite sure that... that something very  _wrong_  just happened. He glanced around, noting that he was standing in Undyne's un-charred kitchen, stirring the pasta sauce as he was earlier. Time had just reverted to before the house caught on fire? This definitely wasn't his doing, so it could only be...

"The anomaly." The human he'd seen in other timelines hadn't nearly reached the Underground yet, so the one who reverted this timeline could only be Flowey. He had mixed feelings about the meddling flower, but whatever was happening elsewhere in the Underground, this reload seemed to be in his favour. He could worry about temporal anomalies AFTER ensuring Undyne's house didn't catch on fire this time. He lowered the spoon and backed away from the counter.

"S-Sorry, Undyne, I... I'm not really feeling up to this right now." Undyne looked a little disappointed, but she didn't protest.

"...Yeah, okay. We can cook some other time, once things are back to normal!" She gave him the best grin she could, but her heart obviously wasn't in it. "So, what should we do now? Do you wanna practice your magic with me? I bet you're a lot stronger like this! When humans fuse in the history tapes Alphys showed me, they always get a huge power boost!" That was when he realized how she'd been taking this so calmly. She only knew about 'fusion' from anime. She must have had several misconceptions about his situation from the start.

"I... do need some practice with control! But I should target the dummy first, until I know my own strength again!"

"Good enough! Now let's get out there and train!" She grabbed his hand and ran, dragging his hand along with her. He followed closely behind her, not daring to bring up the fact that his hands weren't directly attached to his body...

 ---

Once Gaster caught up to his hand, Undyne pointed him at the dummy. "C'mon, give it your best attack! Don't hold back! We can work on holding back once we see your full power!!" His _full_ strength? That could be damaging. But she may have had a point about gauging his full strength first. He could find his limits scientifically, testing his sheer power without any added intent to harm... And he could show Undyne his special attack! Papyrus' boundless enthusiasm seemed to be rubbing off on him, but Gaster couldn't complain. His eyes blazed with magic as he readied his attack.

"Alright! Watch this! Full power... **GASTERBLASTER!** " A giant blaster formed just above his head and shot a blinding beam of energy at the poor dummy. It didn't stand a chance. (At least that ghost was used to getting new dummies, after working with Undyne for so long.)

"Wow. That was... TOTALLY AWESOME!!" Undyne cheered from a few feet away. "I always knew you had it in you!" Gaster couldn't help but grin back. Obliterating the dummy wasn't very helpful in terms of measuring his attack power (beyond "overkill"), but it _was_ pretty cool.

The subsequent power drain was less cool. It took a second to affect him, but he was left feeling a bit wobbly... So, attacking at full strength left him vulnerable. This was good information to have. Ordinarily, he'd just sit down and take a breather, but without clear legs, he just ended up settling into a shorter blob. He was okay with this, but it looked weird enough to worry Undyne.

"Hey, are you okay?"

"I'm fine. I just need a breather."

She squatted down next to him. "Okay, we'll take a break for now. ...Want me to get you some tea or something?" He nodded. Tea was good.

 ---

Undyne returned a few minutes later with two cups of golden flower tea. "Here you go, Pap- No, I should stop calling you that." She passed him his tea, then sat down beside him.

"Undyne, I..." He took the tea and settled into a comfortable position. 

"I know. I know... you're not Papyrus. Not really. So you can stop pretending for my sake." She refused to meet his eyes, staring into her own teacup instead. "I just thought... if I played it cool, acted like nothing was wrong... but it's not the same."

"...I'm sorry. And, uh, you can call me Gaster." He took a sip of his tea—scalding, but delicious. "But you should know that this... can't be undone. I'm not like the fusions from your 'documentaries'. I can't give Papyrus back to you. I shouldn't have given you false hope..." Undyne shut him up with an affectionate slap on what she assumed to be his shoulder.

"Hey, you made a mistake, but you did it for the right reasons. It's hard for me to be upset about that. Besides..." She forced herself to smile at him again. "If you're even half as cool as Papyrus, I'm sure we'll be great friends!"

"...I'd like that."

* * *

 

EDIT: bonus art


	5. Reflection

**Summary for the Chapter:**

> Gaster has a lot to figure out. But as a scientist, figuring things out is his job.

**Notes for the Chapter:**

> So I just figured out the backdating thing, and that it was saying I posted my chapters the day I’d first drafted them and not when they were actually posted? I’ll have to be more careful of that. For now, have some more Gaster. Short-ish chapter this time.

> ENTRY NUMBER 34

All in all, Undyne took the loss of Papyrus surprisingly well. Better than I did, almost. And after properly introducing myself, it looks like we can even be friends again. (Again? For the first time.) However, the temporal anomaly that occurred during our lessons made me realize it may be worth returning to my previous research after all. I can't let Flowey do as he pleases with this timeline, not knowing how he abuses his power to cause harm. On another note, I think I've set a new record for most minor identity crises in the span of a week. And it's barely been four days.

I miss them. They miss them. They miss each other. But we're all together, so we're okay. We'll be okay. I'll be... okay.

 

Gaster returned from his meeting with Undyne late that night, having taken the long way back to the lab from Waterfall. He had needed the time to get everything straightened out in his head. He was still worried about Undyne, part of him was panicking about yet another minor reset, and the red band around his neck never quite went away. He rubbed it idly as he walked, wondering just how much control he really had over what he thought was supposed to be his body.

He had barely made it through the door when Alphys ran up to him, arms full of papers. "H-Hey, Gaster! I finished with Mettaton, and you weren't back yet, so I thought I'd get all your old notes together for you! I mean, all the ones with what looked like your old handwriting that have been here for as long as I can remember. These are yours, right?" She handed him a page from the loose stack she'd collected. It was definitely his handwriting, with scribbled notes and theories surrounding a rough preliminary sketch of the CORE.

**Thank you,** he signed before taking the rest of his notes off her hands. If there was anything that could make him feel like _himself,_ it would be throwing himself into his work.

"Y-You're welcome!" He was about to head upstairs to the desk, but Alphys spoke up again before he could leave. "...Uh, what happened to your neck? It wasn't... red before..." Why did she have to ask that while his hands were full? He couldn’t sign back, but he didn’t want to just ignore her…

"Papyrus." That one word held enough regret for two monsters.

"O-Oh... Is he still...?"

"We're still getting used to this."

"..." Alphys didn't really know where to look. Anywhere but at Gaster seemed good. "...Sorry. I'll, uh, go get the rest of those notes for you." She skittered off, leaving Gaster alone with his papers and his thoughts.

 

Gaster spent the rest of that night sorting through stacks of old papers and listening to whatever Alphys was watching. (The opening theme to Mew Mew Kissy Cutie was surprisingly catchy.) A good chunk of the notes were about the CORE, or the DT Extractor, which weren't as useful now that those projects had been completed, but they were good for reminiscing. He could remember writing many of those scribbled lines, over several late nights at his old desk, before everything was ripped apart. Long before Sans and Papyrus ever existed, before he'd even considered his temporal studies.

Temporal studies... There were a few pages of notes on that, too. Theories and sketches trying to visualize timelines (many of which he now knew to be invalid or inaccurate), concepts and plans for machines to see forwards and backwards in time (definitely not something he needed anymore even if he could get any further in development), and a single page of notes on a certain machine... The machine that destroyed him.

Gaster had learned the hard way not to mess with space-time. But it seemed a certain flower had yet to learn that lesson. Papyrus had been fond of Flowey, but between the resets and manipulating his brother, Sans couldn't stand the miserable little weed. Gaster as a whole wasn't entirely sure how _he_ felt about Flowey, but he knew he needed to be stopped. However, openly opposing him wasn't an option; if Flowey saw Gaster as a threat, he could theoretically rewind the timeline to before he was 'formed' and prevent it, effectively destroying him. So Gaster would lie low for now, hoping that Flowey didn't decide to reset that far without provocation until the human fell.

Once the human fell, the timeline wouldn't be able to revert to before that point, securing Gaster's continued existence. But the human themselves were a wild card. It was impossible for him to predict their initial disposition. Would they fight? Would they kill? Entire collections of timelines had been (would be?) erased by a murderous child's actions. But a pacifistic human would be able to bring about the destruction of the barrier and free all monsters, granting this timeline a happy ending.

Gaster could only hope he got a good human.

**Notes for the Chapter:**

> That red scarf isn't going away. It's a permanent reminder of Papyrus. If Sans ever decides to assert himself, he'll probably show up too.


	6. Fraternization

**Summary for the Chapter:**

> Gaster meets with an old friend for a cup of tea and to catch up on lost time.

> ENTRY NUMBER 35

Flowey must be stopped. ...That's what I'd like to say, but I don't really have the means to stand against him at this point. The truth is, I know **what** he does to the timeline, but I still haven't figured out **how**. The most obvious course of action is for me to research this. With my unique relationship with the space-time continuum, and Alphys' notes on Flowey's origins, I should be able to figure out **something**. Alphys may even be able to help.

I've been considering resuming my former position as Royal Scientist, if I can. But to do that, I'll need to talk to ASGORE. I... doubt he'll remember me much more than Alphys did, considering my erasure, but I would love to share a cup of tea with my old friend.

 

 **Good morning, Alphys.** Gaster seemed far cheerier than he had been last night. **What are you up to?**

"G-Good morning, Gaster! I'm just, uh, working here." Alphys was glad to see him happy, but she couldn't stop glancing at his 'scarf'. Papyrus was stuck like that, forced into an amalgamate (albeit one with a clear dominant personality, but that wasn't necessarily better). And it was all her fau-

Gaster interrupted her train of thought with a friendly hand on her shoulder, as he had the other night. "Don't blame yourself." There was something familiar about the gesture, though she wasn't quite sure why. But there was something more obviously familiar about the lopsided smile he was giving her. _Sans._ " Hey, how would you feel about helping me with some of my old work?"

"Your old... work? What kind of work?"

Gaster let go of her shoulder to continue signing. **Temporal analysis. I want to go in a new direction from my old research, but I'll need resources that only the Royal Scientist has access to.**

"Temporal analysis? I, uh, don't know much about that field, but I'll help however I can!" Not that she expected to be much help, but he could at least bounce ideas off of her and get her to hold things. "But if it's resources you need, you may as well just take your job back..." Wait, she hadn't meant to say that out loud.

 **Well, if that's what you really want...** Gaster looked away. **I wasn't just going to take it from you, but I... It would be nice to have my old job back.**

"Then take it!" She said that a little more forcefully than intended, but she'd already come this far... "You're probably more qualified than I am anyway! I can talk to King Asgore about... getting things set up..."

 **I'll talk to him. I've been meaning to see him anyway.** Honestly, Alphys was relieved at that. She would much rather stay in the lab, hide her mistakes, and let Gaster handle the talking part. **I'll head out shortly. Knowing Asgore, he'll probably be in his garden at this time of day.** By 'shortly', he obviously meant 'immediately', because the moment Alphys looked away, he was gone. Sans and his shortcuts...

 

"ASGORE."

The king looked up from the flowers he was tending, and looked towards the door, but his guest wasn't there. "Howdy," he greeted them regardless. "Do you need me for something?"

"Look at me, Fluffybuns."

Asgore turned again, following the sound of the distorted voice, to see Gaster move into the sunlight. "I don't think I've seen your face before... No, wait, I have, but it must've been a while." His fuzzy face scrunched up in confusion. "Say, what's your name?"

"You used to understand me," he muttered as he signed his name. **GASTER.**

"G-Gaster...?" Asgore stared a moment more, head tilted like a puzzled puppy. "I... should know you, shouldn't I? I just can't quite... Ah, nevermind that. I'm sure it will come to me eventually. For now, can I interest you in a cup of tea?" He smiled warmly as he set down his watering can (a tiny thing, dwarfed by his massive hands).

Gaster nodded, smiling wider than he ever had since his return. He and the king had been very close before the accident. Asgore may not have been particularly knowledgeable about Gaster's fields of study, but he was unfailingly pleasant to talk to. Gaster had worked through numerous problems in his designs just by explaining to Asgore how each part should work and how they fit together, picking up on any discrepancies as he talked. And sometimes the king would force him to take a break from his research after one too many sleepless nights in front of his desk. The thought of Asgore having any recollection of their old partnership, however faint, was a happy thought indeed.

"I'll go put the kettle on, then. Is golden flower tea okay, or would you like something else?" Gaster signed that any tea was fine, and followed his old friend to his modest living space.

Gaster almost expected to see Toriel in the kitchen, given the familiarity of the rest of the situation, but of course she wasn't. She had left years ago, some time after Gaster had been shattered. He had no memory of the exact circumstances, but he did know that the former queen had holed herself up in the ruins of Old Home. (Now that he thought about it, Sans hadn't paid his joke buddy a visit in quite some time. He'd have to stop by the old door sometime soon.) He eased himself into a seat at the table as Asgore prepared the tea in the kitchen.

The flowers on the table were new, though. The golden flowers that now filled Asgore's house weren't the same buttercups and forget-me-nots Gaster was used to seeing. He vaguely recalled this breed of flower being introduced to the underground after the tragedy that tore apart the Dreemurr family, but it was less of a proper memory and more like something he'd read from a book. He didn't have much knowledge of the years immediately following his own disaster (the Gaster Disaster, that had a nice ring to it), not until the point in time where Sans and Papyrus had appeared. And... what kind of tea did he agree to? Perhaps Asgore had been able to make tea from these flowers. Well, he'd try any tea once.

It didn't take long for Asgore to return to the table with a large teapot, a small teacup with a saucer, and a large mug, all full of sweet-smelling tea. "Here you go, Gaster." The king carefully passed Gaster the cup, taking the mug for himself in his other hand. "I hope it's not too hot for you."

 **Thank you,** Gaster signed before taking a sip of the tea. _Not bad._

"So... Was there something you wanted to discuss? Maybe remind me why you're so familiar?" Asgore was obviously uneasy, but refused to let that get in the way of being a good host.

He started off with what he told Alphys days ago. **I was the Royal Scientist before Alphys. I designed and helped build the CORE. I was researching the malleability of the space-time continuum when one of my inventions malfunctioned, and I was almost entirely erased, scattered across time and space with barely a trace of me remaining aside from my work. So... that's why you can't remember me. It's a side-effect.**

"The malleability of what now?" Asgore drank a large mouthful of tea, processing Gaster's explanation. "Oh, I think I get it. You made all our current technological advances possible, but then something went wrong and you disappeared so completely no one could even remember you were ever there." Another sip of tea, to give him an excuse not to keep talking as he gathered his thoughts. "But then... how can you be here?"

 **I've sort of... regrouped.** He stopped signing to take a sip of his own tea. **Enough of me was in the same place at the same time... It's complicated, and I'm not entirely back to normal, but I'm _here._ I'm _now._ And I want to get back to my research.**

"Alright... But your old position isn't exactly open. I'd need to-"

**I've already discussed this with Alphys. In fact, she's the one who helped... reassemble me. She's happy to assist me in my continued temporal studies.**

"You mean you're planning to continue the experiments that destroyed you before?"

**Not the same one, just in the same field. Actually, my experience has given me unique insight as to how time actually works. My last project wouldn't have worked even if I had been able to complete it. But now I have a new direction I want to take with this research. I just need a guaranteed source of resources.**

"Well, I can do that! If you're sure Alphys is comfortable giving you her position, then by all means, continue! I trust you know what you're doing." Most of his tea was gone, and his uncertainty had disappeared with it. "And feel free to stop by and chat any time! I miss having someone to talk to like this. I've barely heard from Alphys in years."

 **I will, old friend.** Gaster got up from his seat with a smile and quickly finished the rest of his tea. **For now, I'm off to the lab.** He left the room, taking another shortcut to reach the lab before Asgore even registered that he was gone.

**Notes for the Chapter:**

> ~~in computer science terms, Asgore is an excellent rubber duck~~


	7. Hesitation

**Summary for the Chapter:**

> It's time for a long-overdue talk with an old pun-buddy by an older door. But how much has to be said...?

**Notes for the Chapter:**

> Whoops, sorry this took me almost two months to write. Toriel was not cooperating, there was work to be done, and all my free time disappeared... This chapter's gonna be dialogue-heavy. And pun-heavy. It was inevitable.

> ENTRY NUMBER 36

Gaster's got his old job back. I'm just his assistant now. (What a relief.) He's already briefed me on our new area of study: temporal manipulation and memory. I don't really understand his talk of SAVEs, LOADs, and RESETs yet, but apparently there's something out there that's been using the flow of time like its personal plaything, and Gaster thinks the first step to stopping it is developing some way for me and other people to remember what happened in the time that was reverted. (He says he already remembers that kind of thing, and that a minor reset happened while he was at Undyne's the other day. Spooky.)

We'll start work tomorrow evening. Tonight we're supposed to get some rest, and tomorrow morning Gaster said there's something personal he has to do. The way he said that—with Sans' voice again—makes me think he's going to Snowdin for something. I probably don't want to know what he's up to.

 

It was a beautiful day outside. Or at least he liked to think it was. It was certainly beautiful inside the caves of Snowdin that morning, as he followed the old familiar road to the door to the ruins. After catching up with Asgore yesterday, it was time for him to face a part of himself that had until now been content to stay back and watch life go on without him.

"Alright, lazybones, time to see who's there." It was hard to call the movement of his blobby fascimile of a body 'walking', but he approached the door at an approximate walking pace nonetheless. He reached out and knocked on the old door before settling himself into a sitting position.

"Who is there?" Right on cue. Now, the joking began.

"Boo."

"Boo who?"

"Hey, don't cry! I haven't been gone that long, have I?" That got a laugh out of her. Just the sound of her was enough to make him laugh too.

"My turn! Knock knock!" She knocked against the door as she spoke. The usual joking went back and forth for several rounds after that. It felt... _right._ He was so relaxed, thinking of nothing but the next punchline, that he didn't notice his body shifting, as his inky black torso-analogue turned midnight blue.

"Knock knock!"

"Who's there?"

"I am!"

"...I am who?"

"Oh, do you not know who you are?" Ouch, that hit a little close to home. He couldn't muster up the usual level of chuckles at that one.

"Heh heh... About that..."

"Is there something troubling you?"

Yes, there was something troubling him. There were a myriad of things troubling him. But... Toriel only knew Sans by his voice. She couldn't tell that anything had changed about him. Maybe... Maybe that was for the best.

"Eh, don't worry about it. I've just been going through some stuff, nothing major."

"Well, if you insist... Say, how did that pie recipe turn out? Have you tried it yet?"

"Oh, uh..." He remembered that recipe. Toriel had told it to Sans through the door a few weeks ago, he'd written it down and taken it home to try, but... "Some of the ingredients were kinda hard to find, and I think I burnt it a little, but I think it turned out pretty well for a first try."

"Wonderful! Unfortunately, despite the saying, pie is not actually all that easy..." They both snickered at the joke. "But I am sure you will improve with practice!"

Practice... Would he get a chance to practice piemaking? He knew how he worked. He'd trained himself long ago to come out of his lab for meals, because he'd never take breaks otherwise. Taking some of Sans' laid-back attitude was probably good for him... But if he was going to keep training with Undyne for Papyrus' sake, the least he could do for Sans is bake a few pies and crack a few jokes by the old door for Toriel. And if it got Alphys to eat something other than instant ramen once in a while, then that was another bonus.

"Yeah, practice makes _pie_ -fect." That was a terrible joke and he knew it (in fact, some part of him was screaming internally), but Toriel seemed to enjoy it, judging by the snorts on the other side of the door.

"Perhaps once you master that recipe, I could share some more with you? I would love to hear what your brother thinks of your cooking!" Oh, right... Before, Sans used to tell Toriel about Papyrus in between jokes. But now, what was there to tell her?

"Y-Yeah, I'll... have to get back to you on that. Speaking of which, I oughta get going. My bro's... probably waiting for me." Sans' voice was better for lying, but he still hated it as a whole. He just didn't have it in him to explain things just yet. He 'stood' away from the door, awkwardly rubbing his... floof? When did that get there? He looked down at himself to find a band of off-white fur around his shoulders, resembling the hood of Sans' old jacket. "Fascinating..."

"Oh, is it time for you to leave already? Well, I will not keep you any longer." He could practically hear Toriel smiling from the other side of the door. "Give your brother my regards!"

"Yeah, I will," Gaster replied, but he really didn't need to. After all...

His brother was right here.


	8. Intermission

**Summary for the Chapter:**

> Time flies, Gaster and Alphys have fun. A month passes in the blink of an eye...

**Notes for the Chapter:**

> Sorry for dropping off the face of the earth (again, for a whole year), but since I do actually have a plot outline for this fic, I _will_ try to continue it (slowly). This chapter goes out to Flarga, for reminding me I still have an audience here!  
>  Hope you like log entries, because that's all you're getting for now. Lots and lots of log entries.

 

> ENTRY NUMBER 37

Gaster didn't get back from his trip to Snowdin for a while, but when he got back, his hands were full of new notes. He said something about bringing them from his old house. I had no idea Sans still did anything science-y after... Well, after Gaster split, I guess. Come to think of it, I feel like Sans might have mentioned Gaster a long time ago, soon after we first met... Just how much did he know? Was putting Gaster back together Sans' plan from the beginning?

Anyway, whatever Sans was doing at his house, Gaster's got the notes back now. (And a few other things from his house.) He's been weirdly quiet since then, though, like he's upset about something... And he looks different for some reason? But I didn't want to bring it up.

 

> ENTRY NUMBER 38

We've been working on a way to preserve memory through resets, to find a way to combat 'the anomaly'. Gaster won't tell me who or what the anomaly _is,_ but I can tell he's scared of it. Our first step is to preserve these logs, so if anything timey wimey _does_ happen, we won't be set back. Gaster's got some kind of a safe in mind to store our notes. He's working on building a prototype now, so I'll put this log in there when he's done.

 

> ENTRY NUMBER 39

Gaster tried making a pie today. I'm not sure where he got the recipe, but it was a nice change from all the noodles... even if it was a little burnt. He was taking a lot of notes, as if it was another experiment. I can't read his weird handwriting, but I _think_ he's trying to treat cooking like another branch of science...

 

> ENTRY NUMBER 40

Gaster came down to the lower labs with me today. He wanted to meet the other amalgamates, though he didn't seem to be too comfortable around them once he was face-to-face with them... Endogeny seems to really like him, though.

He promised not to tell anyone else about them, saying it 'wasn't his secret to tell'... But I know he's ashamed of what I did. He wouldn't look me in the eye when we got back to the main lab.

 

> ENTRY NUMBER 41

My work on Mettaton's new body is going... slowly. But I'm making progress. He's about as bishounen as I can make him... Gaster doesn't have much of a background in robotics, so he's just been watching and asking questions. It felt kinda weird working with him at first, but now it's sort of fun to be better than him at something!

 

> ENTRY NUMBER 42

Something really weird happened when we were working on Mettaton's body. Gaster was holding some parts for me, when I knocked a part off the table, and he just... made a third hand?? And grabbed it??? He looked just as shocked as I was, but at least nothing got broken... And now he's 50% better at holding stuff.

 

> ENTRY NUMBER 43

We've finished the prototype time safe. All our logs go in there now. There's no way to tell if it worked until a reset happens, though. I don't really want to have to test it... The idea of forgetting everything suddenly is kind of scary.

 

> ENTRY NUMBER 44

We took the day off today. Gaster went to visit Asgore while I stayed home and watched anime. As usual. Well, not quite as usual. I've been doing a lot more actual work since Gaster got his job back. Maybe I'm just not cut out for being my own boss...

 

> ENTRY NUMBER 45

Gaster's been experimenting with that 'third hand' thing from before. Once he knew he could have more than two hands, he tried to find out how many more hands he could make, and what he could do with them. Apparently he can have up to six, but he's still a little clumsy with using more than two at a time.

At least this way he can hold things and still have hands free to use sign language with me. Weird as the multi-hands thing is, it's still weirder hearing Sans' voice coming out of his mouth...

 

> ENTRY NUMBER 46

I visited Toriel again today. (I've recorded the best of her jokes separately.) She seemed particularly somber when I tried a joke I'd thought up last time I was in New Home... Perhaps I struck a nerve, but she brought up the promise I—Sans—made to her before. The promise to protect any humans who pass through the RUINS. Of course, I reassured her that I have every intention of keeping that promise.

I felt something resonate within me as I left the door, that promise still on my mind. When I passed Sans' old sentry station... I saw something. A twinkling yellow light. And then it _clicked._ The thought of keeping Sans' promise...

It filled me with determination.

 

> ENTRY NUMBER 47

Gaster's cooking lesson at Undyne's didn't go so well this time... I think they got a little too into it? The kitchen was totally trashed... So he brought her back to the lab to hang out? And it kinda turned into an anime marathon? It was... really fun! (Even if I was sweating the whole time...)

 

> ENTRY NUMBER ~~46~~ 48

Gaster asked me to check in the time-safe when he got back from Snowdin today, and... Looks like it worked? I can't remember recording some of these logs, but they were in the safe when I checked. I'll have to tell him about this. (If he doesn't already know. He looked pretty pleased with himself when he was talking to me...)

On the plus side, whatever happened to Undyne's house was undone... But I missed an anime marathon?? How could I forget something like that???

 

> ENTRY NUMBER 49

The anomaly has arrived.

**Notes for the Chapter:**

> I may have slacked off writing this fic, but I've done a lot with this Gaster in the past year! [Here's a picture showing how he's changed during the story so far.](http://68.media.tumblr.com/c0df83b22457f2aa92e1bea030fef4ff/tumblr_ojdz8rlNqA1vkvd8zo1_1280.png)


	9. Salutation

**Summary for the Chapter:**

> Gaster heads to Snowdin to greet the fallen human. But what kind of run are they on...?

> ENTRY NUMBER 50

The security camera feed saw the door to the RUINS opening today. Gaster took one of his shortcuts straight to Snowdin to investigate up close. I guess I'll just keep working, and watch from here...

 

He took a shortcut to his old sentry station the moment he saw the movement on the cameras. He'd known this moment was coming—seen it a hundred times while he was scattered across timelines—but this would be his first time seeing a human up close since... Wait, how long _had_ it been? He'd completely lost track of time. He knew of the first human to fall, Chara, but he had barely interacted with them, and he'd... _shattered_ before any other humans fell. And he must have seen humans when he was on the surface, but he was only a child himself when the Barrier went up. That was so long ago that he could barely remember it...

He stayed off the usual path to observe the human as they wandered out, noting the plastic knife clutched near their chest. And the dust on their sleeves... _Oh no._ There was still a chance that this wasn't the worst-case scenario, but clearly this human needed his guidance to get them back on a better path.

Once the human reached the bridge, he emerged from between the trees and approached them from behind. They hunched their shoulders and refused to turn around, though he was sure they could hear him coming.

He stood behind them for a tense moment before speaking up. "hey, human. don't you know how to greet a new pal?" Alas, he'd come in such a rush, he'd forgotten to bring his whoopie-cushion... though it would probably just get stuck in the hole in his palm anyway. He held a hand out regardless, and tried to look as non-threatening as possible. "turn around and shake my hand."

Responding to his voice, the human slowly turned around and stared up at him. It took them a few extra seconds to process the extended hand, but they refused to shake it. They chose to FIGHT, slashing at him as hard as they could with their dusty knife. Gaster's guard was down, he couldn't avoid being hit...

...Both of them were surprised by how little damage the attack did. It still _hurt,_ but Gaster shook off the injury with a quick wiggle. The human stared up at him in horror as he pulled himself up to his full height, took a deep breath, and... held out his hand again.

"alright, let's try this again." He refused to fight. This human wasn't attacking out of malice, he was sure of it. They were just afraid. (He wasn't _that_ scary, was he?)

The human kept a tight grip on their knife as they stared at the outstretched hand. ...Maybe a pure white disembodied floating hand _did_ look a little scary, but Gaster was determined to set this human on a better path, and the first step to that was befriending them. And the first step to _that_ was probably not attacking a small frightened child, no matter how dusty they may have left the Ruins.

Neither of them moved for a few minutes. The human continued staring at Gaster's hand, their eyes slowly filling with tears. Finally, they lowered their knife and started to sign something.

He pulled his hand back to respond. **I can sign too, if you like. And no, I'm not going to hurt you.** He could go without the handshake for now. **I promised a friend of mine that I would watch over and protect any human who comes through the Ruins door.** Their eyes widened at that. He had meant to sound comforting, but now they were crying even more than before...

"h-hey, c'mon, kid..." Much as he would love to give them a comforting hug, he doesn't want to touch them in case he scares them more. "whatever happened in the ruins, you've got a chance to start fresh out here. i won't hurt you, and i won't let anyone _else_ hurt you either, okay? "

They lowered their head and signed frantic apologies. Whatever had happened in the Ruins, they clearly weren't proud of it. They also mentioned something about a scary flower...

"it's okay. you made mistakes, but you can do better next time." He wouldn't be taking all this so lightly if he didn't know they had all the tries they needed to do the right thing. All they have to do is try. He holds his hands out to offer them a hug, unsure if they'd be willing to take him up on that...

They don't hug him, but they _do_ grab one of his hands and shake it vigorously. Well, that's a good enough start.

**Notes for the Chapter:**

> Okay, so I am a slow and easily-distracted writer and I have no idea when the next chapter will be done. There is no schedule. But there _is_ an outline, and I _do_ want to keep going as long as people are interested in Gaster's adventures!  
>  As for Frisk, I'll be avoiding typing out any of their dialogue to keep the whole silent protagonist feel, but they _are_ still signing things.


End file.
